Dynamics

Question 1

What are the types of forces

Answer 1

• Contact forces
• Non-contact forces

Question 2

Define mass

Answer 2

Mass is the amount of matter in a body

Question 3

Define weight

Answer 3

Weight is the gravitational force acting on an object that has mass

Question 4

What are the effects of a resultant force on the motion of a body

Answer 4

• Body at rest moves
• Moving body increases speed
• Moving body decreases speed
• Moving body changes direction

Question 4

What is Newton’s Second Law of motion

Answer 4

Newton’s Second Law of motion states that acceleration of an object is directly proportional to the net force acting on it and is inversely proportional to its mass

Question 4

Define inertia

Answer 4

Inertia of an object is the reluctance of the object to change its state of rest or motion due to its mass

Question 5

Define a gravitational field

Answer 5

A gravitational field is a region in which a mass experiences a force due to gravitational attraction

Question 6

What is Newton’s First Law of motion

Answer 6

Newton’s First Law of motion states that every object will continue in its state of rest or uniform motion in a straight line unless a resultant force acts on it

Question 7

What is Newton’s Third Law of motion

Answer 7

Newton’s Third Law of motion states that if body A exerts a force AB on body B, then body B will exert an equal and opposite force BA on body A

Question 8

What are the pair of equal and opposite forces called

Answer 8

Action reaction forces

Question 9

Define friction

Answer 9

Friction is the contact force that opposes or tends to oppose motion between surfaces in contact

Question 9

Define terminal velocity

Answer 9

Terminal velocity is when air resistance equals the weight of the falling object such that there is zero acceleration and object falls with constant velocity

Question 10

What are the factors affecting terminal velocity

Answer 10

• Larger weight = larger terminal velocity
• Larger surface area = smaller terminal velocity

Question 11

How do objects fall with air resistance

Answer 11

• Air resistance increases as speed of falling object increases

Question 12

What happens when there is a net force acting on an object initially at rest

Answer 12

Object has uniform acceleration

Question 13

What happens when balanced forces applied to object initially moving with constant velocity

Answer 13

Object continues moving at same constant velocity

Question 14

What happens when net force applied to object initially moving with constant velocity

Answer 14

Object has uniform acceleration

Question 15

What happens when net force against direction of initial motion applied to object initially moving at constant velocity

Answer 15

• Object has uniform deceleration in same direction of initial motion
• Stops instantaneously
• Uniform acceleration in direction of net force